This question is not about visual diff -- i.e. file comparison.
Is there a tool which let me compare directory A and B (recursively), and as the output I would get two panes, with lists -- files in A (as linear list, not a tree) that are missing in B, and in the second -- files in B which are missing in A. And then I could select some of those files, copy them, remove them, rename them, etc.
The comparison base on file name and file size is enough for me.
There is perfect tool for this needs, and it is called Komparator (don't confuse it with Kompare) -- it comes with... KDE 3.5. Since I try to migrate from KDE 3.5, I am looking for something "modern".
I checked grsync, but it for automatic syncing directories, less for showing differences and manual operations (unless I miss something).